Phosphonic acid esters and process for their production



United States Patent The present invention relates to and has as its objects new and useful phosphonic acid esters and processes for their production. Generally the new compound of this invention may be called phosphonic acid esters of the enolic ester type and thus they may be represented by the following formula In this formula R stands for aliphatic or aromatic radicals, R stands for aliphatic radicals, X and Y stand for oxygen or sulfur, and Z stands for further atoms necessary to complete a compound which is able to react in the ketoor enol-form, and which in the instant case as said above is present in the state of the enolic ester type.

Phosphoric acid esters of the above mentioned type recently have become of importance of the insecticidal or generally pesticidal type. For thus in US. Patents No. 2,754,243 and No. 2,854,244 a number of compounds have been described which may .be considered as somewhat related to the above said formula with the exception that instead of phosphoric acid esters the compounds of the present invention are derivatives of the phosphonic acid ester type.

It has been found that the new and valuable class of insecticidal phosphonic acid esters can be obtained by reacting enolisable ketoor thioketo-compounds with O- alkyl-thionophosphonic acid halides or phosphonic acid halides. Such enolisable ketoor thioketo-compounds belong above all to the heterocyclic group and are for example (the designation means in the following either the enolor keto-form,'the notation which has become most familiar in organic chemistry): dioxotetra hydrofuran derivatives, and pyrazolones, such as e.g.,

pyrazolone- 3-methyl-pyrazolone( 5 1-methyl-pyrazolone-(5 l-ethyl-S-methyl-pyrazolone-(3 l-phenyl-pyrazolone-'( 3 1-phenyl-5-methyl-pyrazolone-( 3 1-phenyl-4-methyl-pyrazolone-(3 l-phenyl-4.S-dimethyl-pyrazolone (3 3.5-diketo-pyrazolidines,

such as 1-methyl-3.S-diketo-pyrazolidine, 1-phenyl-3.S-diketo-pyrazolidine, 3-methyl-isoxazolone- (5 3-phenyl-isoxazolone-(5 imidazolone-(Z l-phenyl-imidazolone- (2) 4-methyl-2-hydroxythiazole, 4-phenyl-2-hydroxy-thiazole, triazolones, as, e.g., l-phenyl-S-hydroxy-1;2.3-triazole, l-phenyl-S-methyl-1.2.4-triazolone-(3 l-phenyl-S -propyl-1 .2.4-triazolone- (3 3-phenyll .2.4-ox-diazolone(5) 3-methyl-pyrone-(2) -one-'(4) 2rnethyl-3-hydroxy-'y-pyron,

3,216,894 Patented Nov. 9, 1965 ice 4.6-dimet-hylpyridone- (2) 2.6-dimethyl-4-hydroxy-pyridine, B-methyl-pyridazone, 2.4-dimethyl-6-hydroxy-pyrimidine, 5.6-dipheny1-3-hydroxy-1.2.4-triazine, 2-methyl-5-hydroxy-1.3.4 ox-diazine, 4-methyl-Z-mercaptothiazole, l-methyl-Z-mercaptotriazole-( 1.3 .4), 1-phenyl-3-methyl-pyrazole-thione- 5 imidazol-thione-(Z) 1-phenyl-imidazole-thiono-(2), Z-mercapto-pyridine, 4-mercapto-pyridine, 6-mercapto-4-methyl-pyrimidine, 6-mercapto-2.4-dimethyl-pyrimidine, 6-mercapto-Z-methylmercapto-pyrimidine.

Besides the aforementioned heterocyclic compounds,

however, simple ketoand thioketo-compounds which are,

enolisable, are likewise suitable for the process of the present invention.

Thus, for example, aceto-acetic acid esters and amides, malonic esters, malonic ester seminitriles, halo-acetoacetic acid amides; chloro-acetic esters, chloro-malonic esters, di-. hydroresorcinols, such as, e.g., 5.5-dialkyl-dihydroresorcinol and similar compounds or their thio-analogues, can

v be used for the process of the present invention.

The reaction is preferably carried out with the alkali metal salts of enolates or with enolates in the presence of alkali metal hydroxides in inert organic solvents at room temperature or slightly elevated temperature.

The new compounds are valuable insecticides, which for the most part possess the advantage over the corresponding phosphoric acid esters, that they are sometimes more readily crystallizable andtherefore simpler in handling and in formulation. The invention concerns compounds which are new insecticides which in part are effective against resistant forms of insect pests.

The compounds obtained according to the invention are preferably applied in combination with the usual extending or diluent agents, as known for other phosphoric acid esters. When using liquid combinations it is expedient to use commercial emulsifiers for improved distribution of the active compounds-especially in water.

As examples for the special utility of the compounds of the present invention the compounds of the following formulae have been tested against aphids. and flies respectively. Aqueous solutions of the aforementioned compounds have been prepared by admixing them with the same amount of an auxiliary solvent (acetone). A commercial emulsifier (benzyl hydroxy diphenyl polgylcol ether) is added in an amount of 20% referred to active ingredient. This premixture then is diluted with water to the desired concentration. The tests have been carried out as follows: (a) against aphids (species Doralis fabae). Heavily infested bean plants (Vitia faba) have been sprayed drip wet with solution of Compound I prepared as indicated above in a concentration of 0.01%. The effect has been determined by evaluation after 24 hours by counting the dead pests either on the surface of the soil or still remaining on the plants, thereby complete killing has been obtained; (b) against flies (Musca domestica). About 50 flies are placed under covered petri dishes in which drop wet filter paper has been placed which is sprayed with an insecticidal solution of Compound II prepared as shown above in a concentration of 0.00001%. The living status of the flies has been determined after 24 hours, and complete killing has been obtained.

The following examples are given to illustrate the present invention:

41 grams (0.4 mol) of 2.4-dirnethyl-6-hydroxypyrimidine and 47 grams (0.4 mol) of potassium carbonate are warmed in 250 ml of dimethyl formamide for 30 minutes to 5060 C. Then 58 grams (0.4 mol) of methyl thionophosphonic acid methyl ester chloride are added dropwise. The heat elfect is thereby weak. After stirring for half an hour at 60-70 C. the mixture is allowed to cool and the solvent distilled off. The residue is poured into little water. The oil is taken up in petroleum ether, Washed and dried. After distilling ofi? the solvent the ester is obtained as a rapidly solidifying oil of M.P. 73 C. It is distillable. B.P. 72 C./0.01 mm. Hg. Yield: 46 grams (49.5% of the theoretical). Aphids and spider mites are killed completely with 0.01% solutions.

By strictly the same way there may be obtained the following compounds, if the corresponding analogous starting materials are used:

4 Example 2 OC H 37 grams (0.3 mol) of 2.4-dimethyl-6-hydroxypyrimidine: and 42 grams (0.3 mol) of potassium carbonate are: warmed in 250 ml. of dimethyl formarnide for half ant hour to 80 C. 52 grams (0.33 mol) of methyl thionophosphonic ethyl ester chloride are added dropwise:

with cooling at 60-65 C.; after heating for one hour' at 60 C. it is cooled, poured into 500 ml. of waterandl the ester separating out as an oil taken up with petroleum: ether. After washing with water it is dried over sodium sulfate and distilled. B.P. 68 C./0.01 mm. Hg. Color-- IS Cu 1o(p) H3 S 4 K19 l 03 N OCgHs Example 3 OCH:

52 grams (0.3 mol) of 2-ethyl-mercapto-4-methyl-6- hydroxypyrimidine and 42 grams (0.3 mol) of potassium: carbonate are heated in 250 ml. of dimethyl formamide for half an hour to 5060 C. At this temperature im the course of 20 minutes, 52 grams (0.33 mol) of methyl-- thionophosphonic acid methyl ester chloride are added. dropwise. The reaction is exothermic and the tempera-- ture of the reaction solution slowly rises to 82 C. After stirring for one hour at 60-70 C. it is allowed to cool,. diluted with 500 ml. of water and the oil taken up in petroleum ether. After the usual working up 70 grams of a colorless, viscous oil are obtained, the oil distils at a B.P. 93 C./0.0l mm, Hg. Yield: 83% of the theoretical. Aphids are killed completely with 0.01% and spider mites with 0.001% solutions.

Example 4 N l z ss-kN OCH;

51 grams (0.3 mol) of 2-ethyl-mercapto-4-methyl-6- hydroxypyrimidine and 42 grams (0.3 mol) of potassium carbonate are heated in 250 ml. of dimethyl formamide for 1520 minutes to 5060 C. At this temperature 52 grams of ethyl-thionophosphonic acid methyl ester chloride (0.33 mol) (B.P. 44 C./1 mm. Hg) are then added dropwise. With slight heating efiect the acid chloride reacts. For completion of the reaction heating is continued for an hour at 60-70 C. After cooling it is poured into 500 ml. of Water, the oil taken up in petroleum ether, washed and dried. B.P. 112 C./0.01 mm. Hg. Pale yellow viscous oil. Yield 58 grams (66.2% of the theoretical). Spider mites are killed completely with 0.001% solutions. Systemic action with 0.1% solutions: 100%. The compound also shows an ovicidal activity.

Example 5 To a suspension of 7 grams (0.3 mol) of sodium in 250 ml, of benzene, 15 grams of ethyl alcohol and then 41 grams (0.31 mol) of aceto-acetic acid ester are added dropwise. The mixture is heated to 5060 C. until the sodium has disappeared. At this temperature 48 grams (0.3 mol) of methyl thionophosphonic acid ethyl ester chloride are added dropwise. By occasional cooling, the reaction temperature is maintained at 50-60 C. It is held for two hours at 5060 C., then allowed to cool, and 15 ml. of water are added. It is then poured from the sodium chloride and distilled. 72 grams of a pale yellow, thinly liquid oil are obtained, the oil slightly darkening on standing. The ester boils at 70 C./0.0l mm. Hg. Yield: 95% of the theoretical. Flies are killed completely with 0.0000l% solutions. Systemic action with 0.1% solutions=100%. Caterpillars are killed completely with 0.1% solutions.

By exactly the same Way and using the corresponding analogous starting materials there may be obtained the following compounds:

From 36 grams (0.36 mol) of acetyl acetone in 250 ml. of benzene the corresponding sodium salt is produced with 7.5 grams (0.3 mol) of sodium and 15 grams of ethyl alcohol in the usual way. To this solution there are added dropwise at 50-60 C. 52 grams (0.3 mol) of ethyl-thionophosphonic acid ethyl: ester chloride. The reaction starts without heat eifect. It is then heated for a further two hours at 50-60 C. and allowed to cool, and the sodium chloride filtered 01f. By distillation 30 grams of the ester are obtained as a pale yellow, later darkening, oil of BF. 62 C./0.01 mm. Hg. Flies are killed completely with 0.00001% solutions. Systemic action with 0.1% solutions=%.

By strictly the same way and using the corresponding analogous starting materials there may be obtainedthev following compounds:

P-S C=o 11-0 0 CH3 C 11 0 Ha C a s S ll P-OC=O H-CEN C ZHEO 0 C 2H5 (32H: S II PO-C=C'H-C o 0 02115 C 1150 O CQHB Example 7 52 grams (0.3 mol) of 1-pheny1-3-methyl-pyrazolone- (5) are dissolved in 200 ml. of dimethyl formamide. 42 grams (0.3 mol) of powdered potassium carbonate are added and heated for half an hour to 50-60 C. With cooling, 52 grams (0.33 mol) of methyl-thionophosphonic acid ethyl ester chloride are added dropwise atthistemperature. After an hours warming at 6070 C. the product is filtered ofi with suction, the filtrate poured into water and the oil taken up in benzene. After washing with water and drying over sodium sulfate and distilling oil the solvent 70 grams of a pale yellow oil are obtained, the oil being no longer distillable. Yield: 78.8% of the theoretical. The same ester is obtained if pyridine is used as solvent and acid-binding agent. The yield is then also 78-79% of the theoretical. Spider mites are killed completely With 0.01% solutions. Systemic action with 0.1% solutions: 100%. The compound shows an ovicidal action.

By the same way and using the corresponding analogous starting materials there may be obtained the following compounds:

A solution of 42 grams (0.3 mol) of dimedone in 250 ml. of diinethyl-formamide and 42 grams (0.3 mol) of powdered potassium carbonate are heated for half an hour to 50-60 C. At this temperature 52 grams (0.33 mol) of methyl thionophosphonic acid ethyl ester chloride are added dropwise. The heating effect is small so that cooling is not needed. After one hours heating at 6070 C. the reaction product is poured into 50 ml. of water, the oil is taken up in petroleum ether, briefly washed with a little 2-N caustic soda, finally with Water, dried and distilled. In this way after slight first runnings, an almost colorless oil of B.P. 96 C./0.01 mm. Hg is obtained. Yield: 48 grams corresponding to 61% of the theoretical. Spider mites are killed completely with 0.01% solutions. Systemic action with 0.1% solutions=100%. Caterpillars are killed completely with 0.1% solutions.

By strictly the same way and using the corresponding starting materials there may be obtained the following compounds:

CH3 I OP\ CHa OCZH CH 8 CH=C(CH:)2

\ o-iV We claim: 1. A phosphonic acid ester of the following formula 5 R1 X I wherein R stands for a member selected from the group consisting of phenyl, chlorophenyl, cyclohexyl, lower alkenyl, lower-alkoxy-lower-alkenylene and lower alkyl having up to 8 carbon atoms, R stands for lower alkyl having up to 4 carbon atoms, X and Y stand for members selected from the group consisting of oxygen and sulfur, R stands for lower alkyl having up to 4 carbon atoms and R stands for a member selected from the group consisting of lower alkyl having up to 4 carbon atoms and lower alkylmercapto having up to 4 carbon atoms.

2. The compound of the following formula 3. The compound of the following formula S C H 4. The compound of the following formula N s CH:

5. The compound of the following formula OCH3 6. The compound of the following formula 7. The compound of the following formula C 11 |Sl 8. Phosphonothioates of the structure no s \H wherein R, R and R" are alkyl radicals containing from 1 to 4 carbon atoms.

9. The method of controlling insects which comprises contacting the insects with a toxic amount of a phosphonothioate of the structure IRVING MARCUS, MORRIS O. WOLK, WALTER A.

MODANCE, Examiners. 

9. THE METHOD OF CONTROLLING INSECTS WHICH COMPRISES CONTACTING THE INSECTS WITH A TOXIC AMOUNT OF A PHOSPHONOTHIOATE OF THE STRUCTURE 